You're not far off. Although not a mandatory whole-of-government thing (and hard to stick to when discussing technical issues), the Aus Government research that I know of suggests public comms, ideally, should be pitched at a year 9 reading level.
Hilariously, most drafts I see/do tend to score at the postgrad level.
Hilariously, most drafts I see/do tend to score at the postgrad level.